Nanocomposites and nanomaterials
Fast synthesis of Mg-Al-hydrotalcite derived nanosystems with enhanced catalytic performance in the Guerbet ethanol condensation 
Valihura K.V., Larina O.V., Soloviev S.O.
L.V. Pisarzhevskii Institute of Physical Chemistry of the NAS of Ukraine.
Prospect Nauky, 31, Kyiv-03039, Ukraine.
E-mail: karina.valigura@ukr.net

During the last decades the conversion of biomass-derived ethanol into 1-butanol via Guerbet condensation has a high interest of researchers. This process consists in the carbon chain elongation and involves dehydrogenation, aldol condensation, dehydration and reduction steps [1]. The promising catalysts for the gas phase condensation of ethanol to 1-butanol are Mg-Al-oxide nanosystems, which textural, acid-base and catalytic properties could be regulated by preparation method [2].
A series of hydrotalcite derived Mg-Al oxide systems with Mg/Al atomic ratio of 2(3) were synthesized and marked as Mg-Al-2(3). In conventional method hydrotalcites were kept in mother liquor for 24 h, and in the “fast” method ‒ only for 1 h. Based on the study of Mg-Al oxide catalysts, it was found that reducing the maturation time of the mother liquor after hydrotalcite coprecipitation from 24 to 1 h leads to a notable decrease in size of particles from 80−150 nm to 50−100 nm. Using a number of physicochemical methods, we noted that an implementation of the fast synthesis gave the increase in the volume of mesopores in 1.5 times and the surface concentration of the basic sites of medium strength in 1.6 times, which increases the activity of catalysts and the selectivity of the 1-butanol formation in the process of ethanol Guerbet condensation. The highest 1-buthanol selectivity 64% and yield 23.4% is achieved over sample Mg-Al-2-fast at 548 K. Also, Mg-Al-2-fast demonstrates the high 1-buthanol selectivity remaining on the same level during 12 h time on stream. The obtained catalyst is reusable and its activity is sustainable after at least six catalytic cycles.

1.	Larina O.V., Valihura K.V., P.I. Kyriienko et al. Successive vapour phase Guerbet condensation of ethanol and 1-butanol over Mg-Al oxide catalysts in a flow reactor // Appl. Catal. A: Gen.-2019.-588.-P. 117265.
2.	Valihura K.V., Soloviev S.O. Catalysts for vapor phase condensation of С1-С4 alcohols with carbon chain elongation // Catalysis and petrochemistry. -2020.-29.-P. 1039-1052.32–51.